Tubular steam-boiler.



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I A s. ELLIOTT. TUBULAB. STEAM BOILEB.

APPLICATION FILED PEB. 5,1908.

948,373. Patented Feb. s, 1910.

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UNITED STATES PATENT oFFIoE.

STERLING ELLIOTT, OF EWTON, MASSACHUSETTS.

TUBULAB. STEAM-norma.

Specication of Letters Patent.

Application led February 5, 1908. Serial No. 414,292.

To all whom 'it may concern:

Be it known that I, STERLING ELLIOTT, of Newton, county of Middlesex,State of Massachusetts, have invented an Improvement in TubularSteam-Boilers, of which the following is a specification.

This invention relates to tubular steam boilers. In the manufacture ofboilers `vof this type ithasbeen customary to expand the ends of thetubes into theholes in the tube plates, and to bead or turn the ends ofthe tubes over upon the exterior surfaces of said plates to therebyvconnect thejtubes with the plates. Oftentimes the boiler leaks at thejoints, due to imperfect connections of the tubes therewith, and also toimperfect connections between the shell and tube plate, which is veryobjectionable. Furthermore,

the boiler immediately begins to Icorrode` both interiorly andexteriorly, interiorly by the action of the water which 1s contained init, and exteriorly by the action of the sweat which accumulates on it,when cold, due to'V the moisture of the air condensing on it, and as aresult of such corrosion the life of the boiler is materiallyTshortened.

The invention has for its object to provide all parts of the boiler oressentially all parts thereof, which are exposed to the waterland to theair, but particularly all parts which are exposed to the water, with acovering,

which is united to the surfaces which are.

thus exposed, and which fills all accessible interstices between the endportions of the tubes and the tube plates, said covering` consisting ofa non-corrosive metallic substance having a high melting point, tothereby prevent leakage at the jomts and to prevent corrosion or toretard the action of .corrosion to such an extent as to materiallylengthen vSuch a non-corrosive covering preferablyA extends continuouslyover the entire exterior and interior surfaces of the tubes and of thetube lates to which they are connected but especially extendscontinuously over the surfaces thereof which are exposed to the water,or at least, over the end ortions of the surfaces thus exposed, and ormsfillets around the tubes at the junction of the tubes and the tubelcially over 4the surface thereof whichs exposed to the water.

The invention also has forits object to i provide the boiler with aplurality of outlets for the steam which lead fromthe same lsteam spaceand which are connected to a common delivery pipe, of steam may be takendifferent points.

Figure l is a plan view of a tubular steam boiler embodying thisinvention. Fig. 2 is avertical section of the boiler shown in Fig. l,taken on the dotted line 2 2, one row of tubes. only being shown.v Fig.3 is an enlarged detail of the end portion of one of the tubes showingits connection with the tube plate. Fig. 4 is a detail showing the endportion o f the boilershell. tional detail of one 'of the tubes andportions of the two tube plates and a portion of the shell, the endsonly of which are covered. Fig. 6 is a vertical-section of one of theelements o-f the boiler'havinga contin-. uous non-corrosive metalliccovering united whereby the supply .from the boiler at thereto, and Fig.7 is a vertical section ofV the other element ofthe boiler having aconunited thereto.

Fig. ,5 is'a secai represents the tubes, b the tube plates formed in anywell known or suitable manner, so far as my invention 1s concerned. Theend portions of the tubes are projected into the holes in the tubeplates and slightlyv but not severelyexpanded to thereby conneet themtherewith. The tubes and tube plates, thus assembled, are vin conditionto have applied to them, both intericrly and exteriorly, a non-corrosivemetallic substance having a high melting point which forms a protectingcovering which is united to thel surfaces to which it is applied, `andwhich fills all accessible interstlces at the joints, and forms filletsaround the tubes at the junction of said tubes and tube plates. Theshell c, Ywhen adapted to be attached to the tube plates, is likewise incondition to be similarly treated. As a non-corrosive meltallicsubstance having a high melting point -I prefer to employ brass, but IVmay employ any other suitable material which is adapted for the purpose.I particularly prefer brass for the reason that. its melting point is sohigh that the temperature of the boiler even under cxtraordinarconditions will notI melt it. To easily apply the non-corrosive metallicsubstance to both the interior and exterior surfaces, I prepare a bathof molten brass and into this bath I entirely submerge the assembledt-ubes and tube plates, or I may only dip the .end portions thereof, andalso entirely submcrge the tubular shell, which at such time is notattached to the tube plates, or I may only dip the end portions thereof.In Fig. 2 the parts are represented as entirely cover-ed, and in Fig. 5the end portions only are covered. Previous to attaching the tubes tothe tube plates, both the tubes and tube plates. are subjected to anysuitable abrading treatment or pickling process and the shell islikewisetreated. The brass is caused, by means of a suitable flux, to imite toall of the surfaces with Which it comes in contact. The non-corrosivemetallic substance may, however, be united to the surfaces in any othersuitable manner. Uien the parts are thus coated it will be seen thatboth the interior and exterior surfaces of the tube plates are uniformlycovered and thereby, protected from corrosion, and that the covering isunited to said surfaces, and as said plates are coated previous to theshell c being attached to them, the flanges b thereof are entirelycovered, and thereby protected. Furthermore, that both the exterior andinterior surfaces of the tubes, or at least the end portions thereof,according to the depth the boiler is dipped in the molten metal, areuniformly covered and thereby protected from corrosion, and that thecovering is united to said surfaces. Furthermore, that the coverings ont-he end portions of the tubes and on the tube plates, if the endportions of the assembled parts are separately dipped in the moltenmetal, or the single covering on the tubes and tube plates, if theassembled parts are entirely submerged, is continuous, in thatit extendsover or throughout both the tubes and tube plates, in intimate contacttherewith, in an unbroken or continuouslayer. Furthermore, that allaccessible interstices between the ends of the tubes and the tube plateson the interior surfaces of said tube plates are filled from both sidesof the tube plates, and that at the junction of the tubes and tubeplates fillets, represented at c, Fig. Q, are formed around the tubeswhich are integral with the covering Which is united to tubes and tubeplates, and also with the material which enters the interstices betweensaid tubes and tube plates. By coating the tubes interiorly from end toend, so as to prevent corrosion along their entire length, smooth innersurfaces are produced andfmaintained whichlargely preventsthe depositand accumulation thereon of soot, but coating the tubes exteriorly,where exposed to the action of the water is of the greatest importance.I `urthermore, it will be seen that all the. ex posed surfaces of theshell, or at least the end portions thereof, according to the depth itis dipped in the molten metal, are covered and thereby protected fromcorrosion and that the covering is united Ito the surfaces thereof.Furthermore, that by covering the connected tubes and tube plates in theman ner described or in some equivalent manner, whereby a continuous orintegral covering is provided for and united to said parts, havingintegral illet around the tubes at the junction of the tubes and tubeplates, the tubes need not necessarily be as severely expanded into theholes in the tube plates i. is now the practice, which reduces the costof assembling the parts, and avoids the danger of (glishiug the tubeplates from the combined strain of a number of small severely expandedtubes.

In small boilers having` a large number of tubes the. tubes are placedvery close to,- gether. This increases the liability of crackig the tubeplates between the tubes when said tubes are severely expanded in place,or subsequently when the tubes are rexpanded for the purpose. ofstopping leaks.

()bviatiug the necessity of expanding and Ireexpanding the tubes intothe holes iu the tube plates permits the employment of thinner tubeplates than has heretofore been customary to use with a correspondingincrease in the'heating eti'iciency and a reduction in the cost as wellas weight.

The shell c of t-he boiler may be reinforced by means of bands c or byany other suitable means adapted to encircle it,land in such case thereinforcing means will be applied to the shell before the shell issubjected to treatment, then the shell will be subjected to theaforesaid treatment resulting in both the shell and the reinforcingmeans having a continuous non-corrosive metallic covering or coveringshaving a high melting point, united to its interior and exteriorsurfaces, which tills all accessible interstices between said shell andthe reinforcing means there on. Arranging the reinforcing means on theshell previous to subjecting the shell to treatment permits theemployment of a much thinner shell than has been customary to employwith a corresponding reduction in the cost and weight, and if bands areemployed as the reinforcing means they may be arranged to cross thegrain of the metal of theI shell, and when covered to become practicallyone piece.

The tubular, cylindrical shell -c of the boiler will have attached toits outer side several plates c2, having holes through them arrangedopposite corresponding holes in the shell for the purpose of connectingan indi- -ator thereto or for other purposes. These plates are attachedto the shell before the shell is subjected to treatment and the shellhaving the plates attached to it is then subjected to treatment in themanner before described, resulting in both the shell and plates having acontinuous non-corrosive metallic covering having a high melting ointunited to its interior and exterior sur aces, which enters allaccessible interst-ices between the plates and shell.

In steam boilers there is a tendency for the water to lift when theoutlet valve is opened and in some cases, especially in small boilers.when the pressure is high and the water level also high the water iscarried through thc throttle into the engine with very undesirableresults. Such action not onlyv draws the Water from the boiler with agreat loss of heat, but has abad effect on the running of the engine. Toobvia'te this objection two or more openings are provided in the toptube plate, which are located some distance apart, and made quite small,and said openings uhich serve as outlets leadiiw from the same steamspace are connected by pipes b2 with a common delivery pipe b, whichlatter serves as an outlet common to all the aforesaid small openings inthe top of the boiler. The areas of the several small outlets Willapproximately equal the area of the common outlet. Having thus described'my invention, what I claim as new and desire to secure by LettersIateut is U' l. In a tubular steam boiler, a tube plate anda set oftubes connected therewith, and a continuous non-corrosive metalliccovering having a high melting point united to both the exterior andinterior surfaces of the tubes and to both the interior and exteriorsurfaces of the tube plate, and forming integral fillets around thetubes at the junctions thereof1 With the tube plate, substantially asdescribed.

2. In a tubular steam boiler, a set of tubes and a pair of tube platesto Which said tubes are connected yat their opposite ends, and acontinuous non-corrosive metallic covering having a high melt-ing'pointunited to both the exterior and interior surfaces of the tubes and toboth the exterior and interior surfaces of both tube plates, and formingintegral fillets around the tubes at the junc tions thereof With thetube plate, substantially as described.

3. A tubular steam boiler composed essentially of a pair of tube-platesand a set of tubes attached thereto, entirely coated with a continuous,non-corrosive metallic substance having a high melting point, and ashell, also entirely coated with a like substance, attached to saidtube-plates, substantially as described.

'In testimony whereof, I have signed myname to this specification, inthe presence of two subscribing Witnesses. A

STERLING ELLIOTT.- I/itnesses B. J. NoYEs, H. B. DAVIS.

